At Artemis, couch action (blowjob in public) happens sometimes. It occurs more frequently in the Frankfurt clubs and the NRW Clubs. It's a mix of guys, with the majority of German locals with some tourists in the mix. All the sex happens in the rooms on the upper level and sometimes in the kinos (cinemas).
You get a variety of nationalities working there, German, Polish, Russian, Ukranian, Hungarian, Turkish, Romanian, English, one or two Asian and Indian girls. It's sorta like the "buffet". You walk around (with a bathrobe there), you find a girl that you like and sit down. Mind you, speaking German is a huge plus like it is speaking French in Montreal. But you might find a girl that speaks a little English.
It's not for everyone. It's something different.